OS X Mountain Lion: Edit your list of printers

If you no longer use a printer, you can delete it from your list of available printers.

Choose Apple menu > System Preferences and click Print & Scan.

Select the printer in the list at the left, and click Delete (-).

If you delete the printer that’s set as your default printer, OS X selects another printer as your default. If you want to use a different printer as the default, choose its name from the “Default printer” pop-up menu in Print & Scan preferences.